Long QT Induced by Psychiatric Medication: Associated Risk Factors

Several psychiatric medications, including typical and atypical antipsychotics, have been associated with increased occurrence of sudden cardiac death. On electrocardiogram (ECG), prolongation of the QT interval corrected for heart rate to over 500 ms may portend torsades de pointes, a potentially fatal ventricular arrhythmia. These investigators examined the prevalence of drug-induced long QT and associated risks in all psychiatric inpatients undergoing admission ECGs during a 5-year study in Geneva, Switzerland, where the procedure is generally standard.

Among 6790 admission ECGs, 1852 (27%) were abnormal, 107 of which showed prolonged QT intervals. Researchers determined that 62 met criteria for drug-induced causality (no prolonged QT on pre-prescription ECGs or improved QT after drug discontinuation or dose reduction). Among 23 examined psychiatric medications, 7 were associated with long QT (odds ratios, >3): methadone, haloperidol, promazine/levomepromazine, sertindole, citalopram/escitalopram, fluoxetine, and clotiapine (an antipsychotic not marketed in the U.S.). Additionally, 85.5% of patients with long QT had two or more disease risk factors of hypokalemia, hepatitis C infection, HIV infection, and abnormal T-wave morphology. At follow-up, five patients with long QT experienced sudden cardiac death, and seven patients developed torsades de pointes. However, seven of these patients received methadone for opioid dependence: Drug overdose could not be ruled out as a contributing factor.

Comment

On the one hand, these findings are reassuring, because death attributable to prolonged QT had a low prevalence. Also, such fatalities were often associated with identifiable medical comorbidities as well as specific psychiatric agents. On the other hand, clinicians should be diligent about screening psychiatric patients for medical comorbidities likely to increase the risk for sudden cardiac death when certain medications are prescribed, and should adjust their prescribing habits accordingly.

Editor Disclosures at Time of Publication

Disclosures for Joel Yager, MD at time of publicationEditorial boardsBulletin of the Menninger Clinic; Eating Disorders: Journal of Treatment and Research; Eating Disorders Review (Editor-in-Chief); Harvard Review of Psychiatry; International Journal of Eating Disorders; UpToDateLeadership positions in professional societiesAmerican Psychiatric Association (Chair, Steering Committee and Executive Committee on Practice Guidelines; Co-Chair, DSM5 Clinical and Public Health Committee; Chair, Council on Research and Quality Care)

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